Lithium ion secondary batteries are widely used in portable devices, automobiles, storage batteries, and the like. In lithium ion secondary batteries containing carbon as a negative electrode active material, repetition of a charge-and-discharge cycle causes formation of lithium dendrites on the negative electrode. For this reason, degradation of battery performance, such as increase in resistance and deterioration of cycle performance, is a matter of concern in such a lithium ion secondary battery using a carbon-based negative electrode active material. To address such concerns, metal oxides to replace the above-described carbon-based materials for negative electrodes have been considered.
A negative electrode including a spinel type lithium titanate (Li4Ti5O12) can suppress precipitation of lithium dendrites. It is known that the suppression can minimize risks, such as short circuit, self-discharge, and ignition, and makes it possible to manufacture batteries having excellent life performance. It is also known that a high-power battery can be achieved by increasing a specific surface area.